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Author Topic: History review of Bosch Nickel-Cadmium (Ni-CD) AL60 & AL60 DV chargers  (Read 378 times)

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Offline Kiriakos GR

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Thermistror NTC 6.8K for Bosch Nickel-Cadmium (Ni-CD)
« Reply #10 on: December 23, 2017, 12:55:49 AM »
I am happy to report that I did discover in Taiwan old stock of genuine PHILIPS thermistor.  :)

Philips part code this is  2322-640-63682  Philips 640 series “accuracy line” color coded NTC disc thermistors for general temperature sensing and control applications.
Tolerance: ±5%
B-Value 3977 ±0.75% Ohm ( at 50 Celsius ) (datasheet of 1995)

Yesterday I did my order and this is send with regular airmail speed.
I am getting qty of four of them, one will be installed at my fresh rebuild-ed battery, the second will be installed at used battery pack which came with this charger,  I am now evaluating which cells are good,  and eventually I will replace damaged cells and I will create my second spare battery pack.   ;)
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Offline Kiriakos GR

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Newer Bosch battery style ( thermistor ) and NI-CD charger ( End of 90s )
« Reply #11 on: December 27, 2017, 05:55:34 PM »
While this topic it is about last produced in EU  Bosch rechargeable power drills and chargers,  today I had the opportunity to examine three dead genuine Bosch batteries from next product series (after 90s).

This Bosch No: 2 607 335 273 Battery style introduces slight design differences.
1) Thermistor this is 6K8 but  this is different production with different B-Value.
2) Bosch added one fourth contact with one resistor,  technically this is described as Key contact point (APT contact point named by Bosch), this resistor possibly works for identification, and power-drill this expects to find such a resistor so to identify type of battery and voltage (Use of 18V battery at 12V drill, this would be catastrophic for electronics and DC motor).
3) Third change this is at both battery and charger port, now additional plastic walls added inside and first generation AL60DV & AL60 chargers and batteries cannot be mixed with this newer product design.

Benchmarks which I did at specific (unbranded but by Bosch installed) 6K8 NTC this show that indeed at 25C this is 6.8K but at 50C this NTC resistance now measure 2.8K and this measurement it is a proof of technical changes made at newer produced NI-CD Bosch chargers (electronics operation).  ;)
Therefore specific unbranded NTC this has no compatibility with older 6K8 NTC made by PHILIPS.   
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Offline Kiriakos GR

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Re: History review of Bosch Nickel-Cadmium (Ni-CD) AL60 & AL60 DV chargers
« Reply #12 on: December 27, 2017, 10:18:07 PM »
By studying technology in use behind this old Bosch AL60DV, I did feel that when I will decode it operating modes, I would be surprised and impressed.
And right now I am surprised and impressed !!  8)   

Today I did manage to put together one second battery pack, this having used and usable Ni-CD cells, so to evaluate this charger with out using my fresh build battery pack.
Despite the fact that AL60DV charger this is powered by a regular transformer, this is a true pulse charger with amazing functionality.

My test setup details are that I did use battery cells (battery pack) this be at 60% charged as it proved by the needed charging time.
Charging pulses were at 1A measured by a fast multimeter, but when I did peak measurement this measured an impressive number of 5A.
Trickle charge pulses these are at 400mA average, and double pulses repeat them self's every 400ms.

By using my Oscilloscope I did manage to record pulses exactly as they are speaking of shape.
Previously I did posted few screenshots when I did some quick tests with one battery pack this having several damaged cells and testing results was funny shapes but interesting.  ;D     

I am tremendously satisfied by seeing what AL60DV can do, such powerful pulses they can truly wake up any half-sleeping NI-CD cell, and this will be charged at full capacity no matter what.

From the other hand, AL60DV this is a double sided axe, fresh made NI-CD with fake listed capacity they will actually suffer because this charger it is not a toy.
Additionally any battery packs not having original BOSCH NTC or exact part replacement, these packs are also in danger.

Personally because I did all recent expenses, at getting new cells to rebuild my battery pack, at buying this AL60DV, at buying original thermistors, then one wild thought it did pass from my head, and this is what I will do if my drill goes bad one day due mechanical damage?
And I found the solution in the German eBay for once more time,  and now I am the owner of another Bosch drill, this is GSR 9,6V and comes with two but dead original Bosch batteries.
Drill and dead batteries for 9.99 euro plus 11 euro shipping, and now I do feel secure.   ;D

My own drill this is SR 9,6V (0~500 rpm) and GSR 9,6V this has additional high-speed mode (0~400 rpm & 0~900 rpm selector).
Dead genuine battery pack would be a good resource for genuine NTC in case that information's leaded me to order specific NTC from Taiwan, they were not 100% correct.

Either way, because of my decisions and by spending my own cash in this exploration, any one who will landed in this topic, he will never get misleading information's,
All my orders will arrive in 20 days or so, and my epilogue would be a simple verification of all posted facts.  :)   
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Offline Kiriakos GR

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Re: History review of Bosch Nickel-Cadmium (Ni-CD) AL60 & AL60 DV chargers
« Reply #13 on: December 31, 2017, 04:37:41 PM »
This is one last follow-up regarding pulses:

When you do own a special current clamp  (AC/DC with high bandwidth) for Oscilloscope, this is the best tool for this job about pulses analysis.  8) 
Analysis of pulses by trying to trigger over few millivolt (at volts side)  this is a big challenge for any Oscilloscope, but if you do your analysis by looking at electrical current? At that end, electrical quantities they are much larger and your analysis this is at the safe side.

According my latest and final measurements, AL60DV this is very powerful and very smart made product.
Major benefit of a true pulsing charger as is AL60DV, this is that at charging process this keeps Ni-CD batteries cooler (cell temperature) than using constant current by a regular power supply.
In long term, batteries charged by pulsing charger, they will be less abused due heat at charging process.
Additionally now I am aware that when Ni-CD cells they are at low temperature then they are more willing to absorb energy from the charger.

I did also run some tests, so to discover how accurate it is DV sensing feature at AL60DV, and I am now truly surprised of how remarkably accurate this is implemented.   
 
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Offline Kiriakos GR

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Re: History review of Bosch Nickel-Cadmium (Ni-CD) AL60 & AL60 DV chargers
« Reply #14 on: December 31, 2017, 05:09:23 PM »
This is one follow-up regarding thermistor sensing ability of AL60DV:

By using 1051 Resistance Box (Times Electronics UK) as this to behave as thermistor resistance simulator, I did manage to discover Low & High limits.
Low or High limit, this is a resistance value that internal battery thermistor could be at, and also here is where AL60DV this gets alerted and refuses to operate ( start charging).

Overheat alert: This found to be approximately at 2.1K ~2.2K and I am using the word approximately because there is small influence from the actual temperature of the charger it self.
I do not keep my chargers plugged at Mains when they are not needed, therefore when I am up to using them they are cold, from the other hand when a charger is plugged all day long, internal temperature could be 10C above ambient. 

Frozen battery alert:   This found to be at 23K Ohm.
I am mentioning this just for the fun of it,  I am not living in Siberia to worry about : Frozen battery alert  ;D

By all this knowledge that I have now, I can safely come in a conclusion and this is that any thermistor when this is at working temperature of 50C and this can have 2.2K of  resistance, then this is suitable for operating with an AL60DV.   :)

More Bosch thermistor comparisons will follow later on when I will receive new PHILIPS thermistor's from Taiwan and also two genuine Bosch batteries (with dead cells) that I got from Germany. ;)
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